Uptake, Transport, and Remediation of Arsenic by Algae and Higher Plants

Arsenic (As) pollution is a significant environmental problem. In nature, As exists as inorganic or organic species but is normally not encountered in its elemental state. As is a nonessential metalloid and does not play any biological role in algae, plants and causes toxic response after gaining entry into the cell. Upon translocation to the shoots As can severely impede growth of the plants by slowing or arresting accumulation of biomass, as well as induce loss of fertility, yield, and fruit production. Several reports are there indicating that an elevated concentration of As in soil causes a significant reduction in crop yield. Algae and plants have developed a range of strategies to combat As toxicity including chelation and sub-sequestration of complexes in vacuole. As contamination in human occurs through consumption of cereals, vegetables, and fruits irrigated with As-contaminated water. The consequence is a global epidemic of As poisoning, leading to skin lesion, cancer of bladder, lung, and kidney and other symptoms. Remediation of As-contaminated soil and groundwater, therefore, is an urgent need for providing safe drinking water and food. Among the various bioremediation processes, phytoremediation by algae and plants is quite effective. Phytoremediation strategy involves suitable plants including arsenic hyperaccumulating ferns and some aquatic or terrestrial angiosperms that efficiently remove the metalloid from highly contaminated soil/water. Utilization of transgenic plants is becoming a new promising tool to enhance phytoremediation potential. There is an urgency to have extensive knowledge on arsenic uptake, transport, metabolism, and detoxification in algae as well as plants for improving phytoremediation. The objective of this review is, therefore, to provide an overview about the uptake of the inorganic and organic species of arsenic, their translocation and biochemical fate in algae and plants and to explore the current concepts of phytoremediation along with their limitations and challenges associated with the developed processes.